SEOUL, South Korea — South Korea's president ordered more troops to a front-line island and dumped his defense minister Thursday as the country grappled with lapses in its response to a deadly North Korean artillery strike.

In scenes reminiscent of the Korean War 60 years ago, dazed residents of Yeonpyeong island foraged through blackened rubble for pieces of their lives and lugged their possessions down eerily deserted streets strewn with bent metal after Tuesday's hail of artillery.

The barrage darkened skies, set off fierce blazes, killed four South Koreans and raised fears of an escalation that could lead to full-scale war.

"It was a sea of fire," resident Lee In-ku said, recalling the flames that rolled through the streets of this island that is home to military bases as well as a fishing community famous for its catches of crab.

The spit of land is just seven miles from North Korea, but had only six pieces of artillery.

Despite warnings from North Korea that any new provocation would be met with more attacks, Washington and Seoul pushed ahead with plans for military drills starting Sunday involving a nuclear-powered U.S. aircraft carrier in waters south of this week's skirmish.

'Our sense of crisis'
The exercises will likely anger the North — the regime cited South Korean drills this week as the impetus behind its attack — but the president said the South could little afford to abandon such preparation now.

"We should not ease our sense of crisis in preparation for the possibility of another provocation by North Korea," spokesman Hong Sang-pyo quoted President Lee Myung-bak as saying. "A provocation like this can recur any time."

At an emergency meeting in Seoul, Lee ordered reinforcements for about 4,000 troops on the tense Yellow Sea islands, along with top-level weaponry and upgraded rules of engagement that would create a new category of response when civilian areas are targeted.

Skirmishes between the Korean militaries are not uncommon, but North Korea's heavy bombardment of Yeonpyeong Island was the first naval skirmish since the Korean War to kill civilians.

South Korean troops returned fire and scrambled fighter jets in response to the North Korean attack, but two South Korean marines and two construction workers were killed and at least 18 others wounded.

South Korea has said casualties on the North Korean side were likely significant, but none were immediately reported by the secretive regime.

Marine Lt. Col. Joo Jong-wha acknowledged that the island is acutely short of artillery, saying it has only six pieces: the howitzers used in Tuesday's skirmish.

The heightened inter-Korean animosity is taking place as North Korea undergoes a delicate transition of power from leader Kim Jong Il to his son Kim Jong Un, who is in his late 20s and is expected to eventually succeed his ailing father.

On Thursday, Lee accepted his defense minister's offer to resign after lawmakers lashed out at the government, claiming officials were unprepared for Tuesday's attack and that the military response was too slow.

Even those in Lee's ruling party demanded the dismissal of Defense Minister Kim Tae-young, who was later replaced by Lee's security adviser. Lee Hee-Won, the new minister, is a career military man who advocates a "smart" military able to anticipate and react quickly to North Korea's unpredictable moves.

On the streets of Seoul, people drew comparisons between the attack and the war of the 1950s.

"This is scarier than the Korean War," said Kim Hak-won, 74. "This is the first time I saw a village devastated by bomb shells."

'Warmongers'
Washington and Seoul have ratcheted up pressure on China, North Korea's main ally and biggest benefactor, to restrain Pyongyang.

However, there was no let-up in the typically bellicose language used by North Korea.

"(North Korea) will wage second and even third rounds of attacks without any hesitation, if warmongers in South Korea make reckless military provocations again," the North's KCNA news agency quoted a statement from the military as saying.

"The U.S. cannot evade the blame for the recent shelling," it added. "If the U.S. truly desires detente on the Korean peninsula, it should not thoughtlessly shelter the South Korean puppet forces but strictly control them so that they may not commit any more adventurous military provocations."

Chinese Premier Wen Jiabao responded by calling on all sides to show "maximum restraint" and pushed again to restart the six-nation talks aimed at persuading North Korea to dismantle its nuclear programs in exchange for aid. Foreign Minister Yang Jiechi, meanwhile, canceled a trip to Seoul this week.

North Korea does not recognize the maritime line drawn by U.N. forces and blamed South Korean military maneuvers near Yeonpyeong Island this week for the clash, calling them a violation of its territory.

The disputed waters have been the site of three other deadly naval skirmishes since 1999.

However, the most costly incident was the sinking of a South Korean warship eight months ago that killed 46 sailors in the worst attack on South Korea's military since the war.

Video: Fishing villagers hit hardest by North Korea

Transcript of: Fishing villagers hit hardest by North Korea

CARL QUINTANILLA, anchor:As we were reminded this week there are nearly 30,000
US troops
in
South Korea
, an outpost for
American forces
since the
Korean War
began 60 years ago. The
USS George Washington
will take part in
military
exercises off
Korea
next week. This follows Tuesday's attack by
North Korea
, which rained artillery fire on an
island
near the border, killing four, including two civilians and triggering an international crisis.
NBC
's
Ian Williams
made his way to that
island
today for a firsthand look.

IAN WILLIAMS:reporting: We traveled on one of the first ferries to resume service since Tuesday's attack to the very edge of
North Korean
waters, where the
rocky island
of
Yeonpyeong
sits just a couple of miles from the disputed sea border. The
military
was on high alert in the sky and patrolling the waters. Soldiers checked everybody leaving our boat. There was vigilance, but also bravado.

Unidentified Soldier:

WILLIAMS:'Enemy shells poured down on me, but I stood my ground,' this soldier insisted. But as we discovered, it was civilian areas which bore the brunt of the attack. The barrage of
North Korean
shells Tuesday struck at the very heart of the
island
's small fishing village, home to most of its
1700
civilian residents. There appeared to be no
military
facilities nearby, suggesting the village was deliberately targeted. In one neighborhood I counted 13 shops or homes reduced to burned-out shells during the hour-long attack. Scores of others had been badly damaged. The villagers knew they lived
on the front line
, that theirs could be a precarious existence. But nobody expected this. It seems incredible that only two civilians died. Most were able to reach nearby shelters.

Unidentified Man #1:

WILLIAMS:'A small dot this size fell from the sky,' this man said, 'and it just exploded.'

Unidentified Man #2:

WILLIAMS:While this 71-year-old fisherman told me he'd hidden on his boat when the shells rained in. Today he was collecting belongings before leaving the
island
. Most civilians have now been evacuated, though some insist on staying.
Yeonpyeong
is a heavily fortified
island
, but it clearly wasn't enough to deter the
North
, and the army is pouring in reinforcements, these soldiers heading there today. The government says they have tough new rules of engagement, though these haven't been made public, which is all little comfort to the
island
's fishermen. Their biggest catch used to come from waters close to the border. Now their lives have been shattered by a violent attack from across that disputed line.
Ian Williams
, NBC News, Yeonpyeong
Island
,
South Korea
.

A South Korean border guard mans a post through a fence draped with re-unification ribbons near the border village of Panmunjom in Paju, South Korea, on Dec. 22, 2010. South Korea vowed Wednesday to "punish the enemy" as hundreds of troops, fighter jets, tanks and attack helicopters prepared massive new drills near the heavily armed border a month after a deadly North Korean artillery attack.
(Wally Santana / AP)
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A North Korean defector takes part in a candle light vigil on the eve of the one month anniversary of the North Korea's attack on Yeonpyeong Island in downtown Seoul, South Korea, on Dec. 22.
(Ng Han Guan / AP)
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A combination of photos shows North Korean soldiers taking part in a shooting exercise at a field in Kaepoong county, on the north side of the demilitarized zone (DMZ) separating the two Koreas, in this picture taken from south of the DMZ in Paju, about 31 miles north of Seoul, on Dec. 22.
(Jo Yong-hak / Reuters)
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Bae Bok-soon (R), an older sister of Bae Bok-chul, cries during the funeral for the two civilians who died when North Korea shelled Yeonpyeong Island on November 23, in Incheon, west of Seoul on De. 6.
(Jo Yong-hak / Reuters)
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Crew members watch as an F/A-18E Super Hornet lands on the deck of the aircraft carrier USS George Washington during a naval exercise with South Korea in the Yellow Sea on Tuesday, Nov. 30. The drills come amid heightened tension in the region after a North Korean artillery attack on South Korea's Yeonpyeong island last week.
(Park Ji-hwan / AFP - Getty Images)
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Staff watch radar screens in the Combat Direction Center on the USS George Washington during the military drills off South Korea.
(Wally Santana / AP)
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Former South Korean special agents whose mission was to infiltrate North Korea, sing a military song during a rally on the Yeonpyeong island, South Korea. About 85 former agents, who criticized the North's attack and urged the South Korean government to punish Pyongyang, landed the island Nov. 30 and said they would stay for a week to help with reconstruction.
(Lee Jin-man / AP)
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South Korean marines watch President Lee Myung-Bak's news conference on a television minitor on Yeonpyeong island on Nov. 29. Lee condemned North Korea's recent shelling of the South Korean border island, calling an attack against civilians an "inhumane" crime.
(Jeon Heon-Kyun / EPA)
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South Korean ships stage off the coast of South Korea's Yeonpyeong Island on Nov. 28 as war drills by the United States and South Korea began.
(David Guttenfelder / AP)
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South Korean protesters hold candles during a rally in Seoul opposing the military exercise between South Korea and the United States.
(Park Ji-hwan / AFP - Getty Images)
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South Korean women take cover inside a bomb shelter on Yeonpyeong Island after authorities sounded the alarm over a possible North Korean rocket attack on Nov. 28. It proved to be a false alarm.
(David Guttenfelder / AP)
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A North Korean soldier, right, looks back as she and another soldier patrol on a pathway along the bank of the Yalu River near Sinuiju, North Korea, Nov. 28.
(Andy Wong / AP)
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A South Korean police car is reflected in the shattered glass of a restaurant window along a seaside road on Yeonpyeong island on Nov. 27.
(David Guttenfelder / AP)
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Former South Korean marines burn images of North Korean leader Kim Jong Il, right, and his son Kim Jong Un, during a rally Nov. 27 in Seoul.
(Wally Santana / AP)
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Kim Oh-bock, mother of Seo Jung-woo, a South Korean marine killed in the Nov. 23 North Korean bombardment, cries as she holds his casket during a funeral service Nov. 27 at a military hospital in Seongnam.
(Ahn Young-joon / AP)
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South Korean protesters denouncing North Korean attack on an island close to the border between the two nations burn a North Korean flag in Seoul on Nov. 24. After North Korea's strike, South Korea and the United States said they would launch four-day naval exercises in the Yellow Sea involving an American aircraft carrier.
(Jung Yeon-Je / AFP - Getty Images)
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A picture taken off television shows the moment of impact of one of the artillery shells fired by North Korea onto the South Korean island of Yeonpyeong.
(Reuters TV)
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Related video

This picture taken by a South Korean tourist shows
huge plumes of smoke rising from Yeonpyeong Island in the disputed waters of the Yellow Sea on Nov. 23. North Korea fired dozens of artillery shells onto the South Korean island, killing two people, setting homes ablaze and triggering retaliatory fire by the South. It was one of the most serious clashes between the two sides in decades.
(AFP - Getty Images)
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Editor's note:
This image contains graphic content that some viewers may find disturbing.